Rotary selector switch with improved rotary brush contact assembly



Jan. 9, 1968 p sc w 3,363,068

ROTARY SELECTOR SWITCH WITH IMPROVED ROTARY BRUSH CONTACT ASSEMBLY Filed Oct. 27, 1966 2 Sheets-Sheet 1 FIG. 1 27 3/ l l l I l 0 MIN INVENTO/Q PIERRE P. SCHWAB i 4%??? BV M7 AGE/VT Jan. 9, 1968 P. P. SCHWAB ROTARY SELECTOR SWITCH WITH IMPROVED ROTARY BRUSH CONTACT ASSEMBLY Filed Oct. 27, 1966 2 Sheets-$heet 5- i "i'i' f Y 4/4 F I 3. 5 Q

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lNVE/VTOR PIERRE P. SCHWAB AGENT United States Patent 3 363,068 ROTARY SELECTOR SWlTCH WETH IMPRUVED ROTARY BRUSH CONTACT ASSEMBLY Pierre P. Schwab, River Edge, N..l., assignor to McGraw- Edison Company, Elgin, 11]., a corporation of Delaware Filed 0st. 27, 1966, Ser. No. 589,933 3 Claims. (Cl. 20011) ABSTRACT OF THE DISCLOSURE A rotary selector switch with a stamped contact wafer assembly including a captive rotor brush-contact unit adapted to make a positive electrical circuit connection from an input terminal to the respective output terminals at each position of the switch.

This application relates to rotary wafer-type selector switches adapted for radio frequency circuits.

An object of the invention is to provide a low cost low capacity selector switch which is of a durable and high quality construction.

These and other objects and features of the invention will be apparent from the following description and the appended claims.

In the description of my invention reference is had to the accompanying drawings, of which:

FIGURE 1 is a side elevational view, partly broken away, of a wafer-type rotary selector switch according to my invention;

FIGURE 2 is a rear end view of this switch as seen from the line 22 of FIGURE 1;

FIGURE 3 is a transverse sectional view taken on the line 3-3 of FIGURE 1;

FIGURE 4 is another transverse sectional view of the switch taken on the line 44 of FIGURE 1;

FIGURE 5 is a fractional sectional view to enlarged scale taken through the axis of the switch; and

FIGURE 6 is a partial exploded view illustrating an alternative embodiment of the invention.

The wafer-type selector switch shown in the accompanying drawing comprises a circular front mounting plate 10 having a central tubular bushing staked thereto forming a bearing 11 for a rotor shaft 12. Staked also to the front plate 10 are two diametrically opposite tubular studs 13 which extend rearwardly from the back side of the plate. Traversing these tubular studs are long machine screws 14 on which are mounted one or more selector switches at suitabie space intervals, there being two such switches S and S herein shown by way of example. For instance, on the screws 14 abutting the back ends of the tubular studs 13 are first tubular spacers 15 of insulative material. Against the spacers 15 is located a stator plate 16 of selector switch S having apertures to receive the machine screws 14. Next on the machine screws are two insulative sleeves 15 in end-to-end relation and against the back one of these sleeves is a stator plate 17 of the selector switch S Further on the machine screws 14 against the back side of the stator plate 17 are insulative sleeves 15 against which are tightened nuts 18 threaded on the respective machine screws tosecure the selector switches in fixed spaced relation to the front mounting plate 10.

The stator plates 16 and 17 have central openings receiving respective rotors 19 and 20. The rotor shaft 12 terminates short of the first selector switch S and is provided with a diametrical slot in which is received an extending rotor blade 21 of insulative material secured to the rotor shaft by a cross pin 22. The rotors 19 and 20 have rectangular apertures receiving the rotor blade 21 so as to couple the rotors to the shaft. The rotor shaft 12 is 3,363,068 Patented Jan. 9, 1968 secured against outward movement by an inner retainer rin 23 (FIGURE 5) and against inward movement by abutment of an outer retainer ring 24 against the bearing 11. The rotor is turned by a manual knob 25 secured thereto as by a set screw 26.

The switch has a stop detent mechanism comprising a stop plate 27 overlying the front mounting plate 10. This stop plate has twelve equally spaced peripheral notches 28 (FIGURE 4) to clear the diametrically opposite mounting screws 14 in each of the different twelve positions in which the stop plate can be mounted. Lanced inwardly from the stop plate is a lug 29 which traverses the front mounting plate via a respective rectangular aperture 30 therein, there being twelve such rectangular apertures to allow the stop plate to be located in any one of twelve equally spaced positions. Secured to the rotor 12 against the back end of the bearing 11 is a detent stop disk 31 having a radial finger 32 for abutment against the lug 29 to serve as an adjustable stop for the rotor. Additionally, there is a fixed lug 33 struck inwardly from the front mounting plate 10 at one of the apertures 30 against which the radial finger 32 will abut to serve as a permanent stop for the rotor. In the broader aspects of the invention, as later explained, it will be understood that the permanent stop as well as the adjustable stop may both be eliminated so that the switch may be adjusted into any one of its twelve different positions.

The portion of the rotor shaft 12 extending beyond the bearing 11 has two diametrically opposite flats 34, and the detent stop disk 31 has a non-circular hole fitting this portion of the rotor shaft so that the disk is splined to the shaft. Formed in the rearward side of the disk 31 are twelve corrugations at equal angular intervals about the center of the disk. Mounted rearwardly of the detent stop disk 31 is a detent ball plate 36 of an oval shape (FIG- URE 4) having diametrically opposite notches receiving the tubular studs 13 to hold the detent ball plate from turning about the shaft. This detent ball plate has two diametrically opposite holes receiving respective spherical balls 37 in position to engage the corrugated portion of the detent stop disk 31. Directly behind the detent ball plate is a flat detent spring 38 also of an oval shape having diametrically opposite portions with recesses 39 which engage respective grooves 40 in the tubular studs 13 to hold the detent sprin against movement in both axial and rotational directions. This detent spring provides a yieldable backing for the respective spherical balls 37 to provide a yieldable engagement of the balls with the corrugated portion of the detent stop disk. Since the spherical balls 37 are confined by the detent ball plate and are urged yiel-dably by the detent spring 38 against the detent stop disk 31, the rotor 12 becomes detented in each of twelve equally spaced positions. It is by abutment of the retainer ring 23 against the back wall of the detent ball plate 36 that the shaft 12 is confined against out- .ward movement. A central opening 41 in the detent spring 38 provides clearance for the retainer ring 23.

Each stator plate 16 and 17 is provided with eleven switch contact terminals 42 secured thereto by eyelets 43 in positions corresponding to the positions of the rotor determined by the detent mechanism above described, there being one vacant switch position when the switch i provided with the permanent stop 33 above described. The stator plates are in the form of circular disks of insulative material having large central openings to accommodate the respective rotors 19 and 20. Each rotor comprises a disk 44 of insulative material having a clearance fit in the central opening of the respective stator disk. Each rotor is held captive with the respective stator plate. For example, on the side of the rotor corresponding to the side of the stator plate on which the contact terminals 42 are mounted is an annular contact wiper 45 of a suitable metallic spring material which extends beyond the central opening of the stator plate and which has a contact finger 45a for engaging the ends of the respective terminals 42 as the rotor is turned through its respective switch positions. This contact wiper 45 is also secured to the rotor disk by eyelets 43. Electrically and mechanically secured by the same eyelets 43 to the opposite side of the rotor disk is a common ring wiper 46 of a metallic spring material. This wiper has two diametrically extending portions forming brushes 47 which extend beyond the central opening of the stator plate and ride on a common ring 48 mounted on the back side of the stator disk opposite the contact terminals 42. The common ring 48 is in concentric relation to the shaft of the switch and is held against turning by three anchoring lugs 48a turned inwardly to engage respective apertures in the stator disk. The common ring 48 has one radially extending terminal 49 at the vacant position of the switch terminals 42 before mentioned, which may also be secured to the stator disk by an eyelet 43 (FIG- URES 2 and 3). Thus, an electrical circuit connection is completed from the fixed terminal 49 via the common ring 48, brushes 47, common ring wiper 46, central rotor eyelets 43 and contact wiper 45 to the respective stator terminals 42 depending on the positioning of the switch.

In an alternative embodiment illustrated in FIGURE 6 the stator disk is provided with twelve switch contact terminals 42one at each of the twelve positions of the switch-and the common ring 48 is held in place solely by engagement of the anchor elements 48a with the stator disk and by the common ring wiper 'brushes 47 bearing against the common ring to hold it in engagement with the stator disk. The radial terminal 49a of the common ring is now bent obliquely upwardly away from the stator disk to clear the respective eyelet 43 which holds the switch contact terminal 42 in this twelfth position of the switch. Further, in this alternative embodiment, both the fixed stop 33 and the adjustable stop 29 are removed so that the switch can be turned into each of its twelve respective positions. Thus, the switch has an operative switch position in each of twelve equally spaced detented positions about the shaft of the rotor.

The embodiment of my invention herein particularly shown and described is intended to be illustrative and not necessarily limitative of my invention since the same is subject to changes and modifications without departure from the scope of my invention, which I endeavor to express according to the following claims.

I claim:

1. A wafer-type rotary selector switch comprising a front mounting panel having a central bearing, a rotor shaft journaled in said bearing, mounting rods on said front panel parallel to said shaft, a stator plate of insulative material supported by said mounting rods at right angles to said shaft and having a central opening concentric with the shaft, a set of spaced electrical terminals mounted on one side of said stator plate in an outer circle concentric with said shaft, a common connector ring on the other side of said stator plate in concentric relation with said shaft having anchor elements engaging said stator plate, and a rotor disk of insulative material in the central opening of said stator plate secured to said shaft and having a wiper brush on one side yieldably slidably engaging said common ring and a radial contact finger on the other side electrically connected to said brush for selectively engaging said respective electrical terminals with contact pressure as said rotor is turned to successive switch positions.

2. The wafer-type rotary selector switch set forth in claim 1 including a detent disk at the back side of the mounting plate splined to said rotor and having radial corrugations in a circular arrangement to define the respective positions of said switch, a stationary detent ball plate at the back side of said detent disk held against rotation by said mounting rods, said detent ball plate having a plurality of apertures overlying the corrugations of said detent disk, spherical balls in said respective apertures, and a flat detent spring at the back sideof said detent ball plate secured at its outer edge to said mounting rods against rotational and axial displacement for providing a yieldable backing for said spherical balls whereby the engagement of the spherical balls with said detent disk serves to detent the rotor in its respective switch positions.

3. A wafer-type. rotary selector switch comprising a front mounting panel having a central bearing, a rotor shaft journaled in said bearing, mounting rods on said front panel parallel to said shaft, a stator plate of insulative material supported by said mounting rods at right angles to said shaft and having a central opening concentric with the shaft, a set of spaced electrical terminals mounted on one side of said stator plate in an outer circle concentric with said shaft, a rotor of insulative material in the central opening of said stator plate secured to said shaft, an annular conductor member on one side of said rotor having an outer edge overlapping the inner circular edgeof said stator plate and having a radial contact finger moved successively into contact with the inner end portions of said terminals as said rotor is turned, a conductor ring on the other side of said stator plate located within the circle of said terminals, said ring having anchor elements engaging said stator plate and having a radially extending contact terminal, a brush member on the other side of said rotor having a plurality of radial fingers riding slidably on said ring, and connector elements traversing said rotor for electrically and mechanically connecting said brush member to said annular conductor member whereby the contact finger of said conductor member is caused to exert pressure against said respective terminals and the radial fingers of said brush member to exert pressure against said conductor ring to provide an electrical circuit connection from said radial connector terminal to said respective stator terminals.

References Cited UNITED STATES PATENTS ROBERT K. SCHAEFER, Primary Examiner.

J R. SCOTT, Assistant Examiner. 

